Automated quantification of aligned collagen for human breast carcinoma prognosis

Abstract

Background:Mortality in cancer patients is directly attributable to the ability of cancer cells to metastasize to distant sites from the primary tumor. This migration of tumor cells begins with a remodeling of the local tumor microenvironment, including changes to the extracellular matrix and the recruitment of stromal cells, both of which facilitate invasion of tumor cells into the bloodstream. In breast cancer, it has been proposed that the alignment of collagen fibers surrounding tumor epithelial cells can serve as a quantitative image-based biomarker for survival of invasive ductal carcinoma patients. Specific types of collagen alignment have been identified for their prognostic value and now these tumor associated collagen signatures (TACS) are central to several clinical specimen imaging trials. Here, we implement the semi-automated acquisition and analysis of this TACS candidate biomarker and demonstrate a protocol that will allow consistent scoring to be performed throughout large patient cohorts.Methods:Using large field of view high resolution microscopy techniques, image processing and supervised learning methods, we are able to quantify and score features of collagen fiber alignment with respect to adjacent tumor-stromal boundaries.Results:Our semi-automated technique produced scores that have statistically significant correlation with scores generated by a panel of three human observers. In addition, our system generated classification scores that accurately predicted survival in a cohort of 196 breast cancer patients. Feature rank analysis reveals that TACS positive fibers are more well-aligned with each other, are of generally lower density, and terminate within or near groups of epithelial cells at larger angles of interaction.Conclusion:These results demonstrate the utility of a supervised learning protocol for streamlining the analysis of collagen alignment with respect to tumor stromal boundaries.

Radiation Promptly Alters Cancer Live Cell Metabolic Fluxes: An In Vitro Demonstration

“…This study complements previously reported studies (60–62) by asserting that clinical radiotherapy could be guided and improved by monitoring key cellular processes such as metabolism. Since metabolism plays an important role in cancer invasion and progression (63–65), metabolic profiling may have potential for guiding radiation treatments in the future.…”

Stromal dynamic reciprocity in cancer: intricacies of fibroblastic-ECM interactions

“…When considering the in vivo tumor microenvironment, the ECM is classically much stiffer than its innate counterpart. Typically the ECM is aligned in quantifiable organized type I collagen fiber patterns [14,15,129,130]. It also includes increased ECM cross-linking and fiber density [30,106,131-135].…”

“…For example, using predictors based on the CAF-to-collagen deposition ratio or type I collagen topographical (anisotropic) ECM features, investigators observed a correlation with unfavorable patient survival [76,129,130,136-139]. Others found that actin binding proteins such as palladin, which regulates stromal pro-metastatic CAF and desmoplastic ECM features (e.g., alignment) [140], can be used as a predictive marker of cancer recurrences subsequent to tumor surgical resection [137].…”

“…These types of microenvironmental reactions should be distinguished from tumor-restrictive stroma signatures [141] where, for example, increases in collagen deposition per se, in the absence of increased cellular α-SMA levels, correlates with better patient outcome [76]. Similarly, innate type I collagen topographic signatures in which ECM fibers are isotropic (disorganized) were also determined to correlate with improved patient survival [129,130]. Overall, these findings suggest that increased isotropic-collagen ECM deposition in the absence of activated stromal cellular markers correlates with better patient outcomes.…”

Decoupling the effects of stiffness and fiber density on cellular behaviors via an interpenetrating network of gelatin-methacrylate and collagen

“…Purely synthetic hydrogels, such as polyethylene glycol diacrylate (PEG-DA) scaffolds, can also allow independent manipulation of ligand density and matrix stiffness over a wide range of mechanical properties [29, 30], but, similar to gelatin, lack the ability to recapitulate the fibrous networks of in vivo tissues. This limitation is problematic because fibers may play important roles in directing cell behavior; for example, fibrillar alignment of collagen in breast tumors has been shown to correlate with a worse patient prognosis [31, 32]. The influence of fibrillar structure on cellular outcomes was also highlighted by recent work which described a significant decrease in mouse xenograft tumor growth upon attenuation of fiber formation and crosslinking by inhibition of LOXL2 [33].…”